Global Patent Index - EP 1578053 A1

EP 1578053 A1 20050921 - Data obfuscation

Title (en)

Data obfuscation

Title (de)


Title (fr)

Masquage de données


EP 1578053 A1 20050921 (EN)


EP 04251573 A 20040318


EP 04251573 A 20040318

Abstract (en)

A portion of data is obfuscated by performing a bitwise XOR function between the bits of the data portion and the bits of an associated mask. A mask used to obfuscate a data portion is generated as a function of the memory address of the data portion. A bitfield representing the memory address of the data portion is split into a plurality of subset bitfields. Each subset then forms the input of a corresponding primary randomising unit. Each primary randomising unit is arranged to generate an output bitfield that appears to be randomly correlated with the input, but which may be precisely determined from the input if certain secret information is known. Each primary randomising unit is also arranged so that a distinct output is generated for each distinct input. The output of the primary randomising units form the input into a series of secondary randomising units. Each secondary randomising unit is arranged to receive as an input at least one bit of the output of every primary randomising unit. The secondary randomising units are arranged to generate an output bitfield in a similar manner to the primary randomising units. The output of the secondary randomising units are then combined by concatenation to form a data mask. In one embodiment, each randomising unit comprises a look-up table whose contents are formed by permuting a sequence of ordered integers in a random manner. In this embodiment, the secret information corresponds to the contents of the look-up table. A mask is thus generated from the memory address of a data portion such that a distinct mask is generated for each distinct memory address, and such that there is a quasi-random correlation between the memory address and the corresponding mask.

IPC 1-7

H04L 9/18; H04L 9/06

IPC 8 full level

H04L 9/06 (2006.01); H04L 9/18 (2006.01)

CPC (source: EP)

H04L 9/0662 (2013.01); H04L 2209/04 (2013.01); H04L 2209/12 (2013.01)

Citation (search report)

Designated contracting state (EPC)


DOCDB simple family (publication)

EP 1578053 A1 20050921; US 2007121943 A1 20070531; US 8588406 B2 20131119; WO 2005091550 A1 20050929

DOCDB simple family (application)

EP 04251573 A 20040318; GB 2005001021 W 20050318; US 52377306 A 20060918